refactor: clean up verbose migration comments

Remove redundant Qt6 migration comments that restate obvious API changes:
- QtConcurrent::run parameter order explanations (preserved where lambda wrapping needed)
- QStringRef/QStringView API changes (shortened to essential info)
- QComboBox::activated signal signature change
- QMap::unite() removal semantics
- QAction include path change
- QMouseEvent/QWheelEvent position() API
- QList/QVector equivalence in Qt6
- QFuture continuation API
- Code generation comments

Preserved comments explaining non-obvious Qt6 behavior or necessary
API migration details.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

qt6-after/qt6-migrated-legatus/Lts/Viewer/SituationMap/FunctionDialog/function_dialog.cpp

@@ -2661,7 +2661,7 @@ void FunctionDialog::onRubberbandApply(RB::RubberbandBase *rubberband)
         for (const auto &bufferPoint : qAsConst(bufferVertexList))
         {
           posCont << Point3D::fromQPointF(bufferPoint);
-          qDebug() << LOGFUNCTION << "buffer coordinate : " << bufferPoint ;   // Qt6: fixed/qSetRealNumberPrecision removed
+          qDebug() << LOGFUNCTION << "buffer coordinate : " << bufferPoint;
         }
 
         bufferPolygon->setPositionsTranslated(posCont); // use map coordinates to print the coordinate values